title: Vemurafenib synergizes with nutlin-3 to deplete survivin and suppresses melanoma viability and tumor growth.
abstract: OBJECTIVE
  For patients with advanced melanoma, primary and secondary resistance to selective BRAF inhibition remains one of the most critically compelling challenges. One rationale argues that novel biologically informed strategies are needed to maximally cripple melanoma cells up front before compensatory mechanisms emerge. As p53 is uncommonly mutated in melanoma, restoration of its function represents an attractive adjunct to selective BRAF inhibition.
  
  
  METHODS
  Thirty-seven BRAF(V600E)-mutated melanoma lines were subjected to synergy studies in vitro using a combination of vemurafenib and nutlin-3 (Nt-3). In addition, cellular responses and in vivo efficacy were also determined. We also analyzed changes in the levels of canonical apoptotic/survival factors in response to vemurafenib.
  
  
  RESULTS
  Dual targeting of BRAF(V600E) and Hdm2 with vemurafenib and Nt-3, respectively, synergistically induced apoptosis and suppressed melanoma viability in vitro and tumor growth in vivo. Suppression of p53 in melanoma cells abrogated Nt-3's effects fully and vemurafenib's effects partially. A survey of canonical survival factors revealed that both vemurafenib and Nt-3 independently attenuated levels of the antiapoptotic protein, survivin. Genetic depletion of survivin reproduces the cytotoxic effects of the combination strategy.
  
  
  CONCLUSIONS
  These results show preclinical feasibility for overcoming primary vemurafenib resistance by restoring p53 function. Moreover, it identifies survivin as one downstream mediator of the observed synergism and a potential secondary target.
authors.affiliation: Wellman Center for Photomedicine and Department of Dermatology, MGH Cancer Center, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Ji
authors.forename: Raj
authors.initials: R
authors.lastname: Kumar
authors.forename: Michael
authors.initials: M
authors.lastname: Taylor
authors.forename: Anpuchchelvi
authors.initials: A
authors.lastname: Rajadurai
authors.forename: Alexander
authors.initials: A
authors.lastname: Marzuka-Alcalá
authors.forename: Y Erin
authors.initials: YE
authors.lastname: Chen
authors.forename: Ching-Ni Jenny
authors.initials: CN
authors.lastname: Njauw
authors.forename: Keith
authors.initials: K
authors.lastname: Flaherty
authors.forename: Göran
authors.initials: G
authors.lastname: Jönsson
authors.forename: Hensin
authors.initials: H
authors.lastname: Tsao
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology*; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000378:metabolism*; D008545:Melanoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008954:Models, Biological; D009154:Mutation; D010879:Piperazines / Q000494:pharmacology*; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology*; D000077022:Survivin; D047368:Tumor Burden / Q000187:drug effects; D000077484:Vemurafenib
chemical_list: D000970:Antineoplastic Agents; C107489:BIRC5 protein, human; D007093:Imidazoles; D007211:Indoles; D051034:Inhibitor of Apoptosis Proteins; D010879:Piperazines; D013449:Sulfonamides; D000077022:Survivin; D000077484:Vemurafenib; C482205:nutlin 3; D048493:Proto-Oncogene Proteins B-raf